GUFS32_SEL
ASSYM(KUF32SEL, GSEL(GUFS32_SEL, SEL_UPL));
PCPU_SET(fs32p, &gdt[GUFS32_SEL]);
_ufssel = GSEL(GUFS32_SEL, SEL_UPL);
[GUFS32_SEL] = { /* 2 32 bit %gs Descriptor for user */
pc->pc_fs32p = &gdt[GUFS32_SEL];